BOSTON — Yancy Gates is so big, it seems as if his arms have two different ZIP codes, and such hulking size has been necessary for the Cincinnati forward to lug around loads of criticism.

“He has had the weight of the world on his shoulders for four years,” coach Mick Cronin said.

Gates spurred various recruiters, including a scholarship offer from Ohio State, to play for his hometown university when the basketball program was rebuilding under Cronin, who’s also a Cincinnati native.

Local fans ripped Gates for underachieving early in his career, and barbs turned especially sharp in December when Cincinnati suspended him six games for being the central figure in a brawl against Xavier.

Now there is a lightness about Gates — the first player to lead Cincinnati in rebounding in four consecutive seasons — that belies his 6-foot-9, 260-pound frame.

The senior is at peace, playing some of the best ball of his career, and has the sixth-seeded Bearcats (26-10) back in the Sweet 16 for the first time since 2001. They play No. 2-seeded Ohio State (29-7) tonight in an East Regional semifinal, the first NCAA Tournament matchup between the schools in 50 years.

“It’s fun. I’m enjoying the experience,” Gates said yesterday.

Fun will look like sumo wrestling tonight as Gates — Cincinnati’s lone big man in a four-guard starting lineup — will be bumping and tussling with another 6-9 wide-body listed at 265 pounds in Ohio State sophomore Jared Sullinger.

“Those two are going to go at it,” Cincinnati guard JaQuon Parker said. “I’m looking forward to the matchup itself.”

So are Gates and Sullinger, who know and like each other from one high-school meeting and some time spent together last summer at a basketball camp in Los Angeles.

“Yancy is a funny guy,” Sullinger said. “He’s always joking and always having fun, which is funny because I’m the same way.”

The image of a jokester doesn’t come to mind for many when they picture Gates. He heard people calling him a thug — and worse — after he punched Xavier center Kenny Frease near the end of the Bearcats’ 76-53 loss on Dec. 10.

Cincinnati suspended four players the next day and made them publicly apologize and face media questions. Gates held his head in his hands and wept during the news conference.

“I took my punishment,” he said.

At the time, the Bearcats were 5-3. Cronin scrapped the offense, designed to go through Gates, and switched to a four-guard lineup. Cincinnati then won all six games without Gates.

He returned Jan. 4 to taunts from opposing fans and questions about his future role.

“Would Yancy fit in to the way we were playing?” Cronin asked.

It was the latest question among many about Gates since he signed out of Withrow High School in Cincinnati.

“I was highly recruited and (fans) were expecting that I would come in and right away take the team where it is now,” Gates said.

The Bearcats went 37-30 in his first two seasons, but they went 26-10 last year, finally ending five consecutive years without an NCAA Tournament appearance.

Gates accepted a diminished scoring role after returning from his suspension and concentrated on defense and rebounding .

“Yancy really had to change his basketball personality,” Cronin said, “from being an offensive player to an all-around player. He’s had to be our anchor because we’re smaller.”

Gates was named to the Big East all-tournament team after averaging 16.7 points and 7.0 rebounds as the Bearcats advanced to the title game for the first time. He’s averaging 15.2 points and 7.5 rebounds in his past six games, including NCAA Tournament wins over Texas and Florida State.

“I came here knowing the program was in rebuilding mode,” said Gates, one of only six players in Cincinnati history with more than 1,400 points and 900 rebounds. “I knew I could come here and help other players to look in and say it’s not such a bad idea. You look up now … we’re in the Sweet 16, and it makes it all worth it.”

On Sunday, Cronin hugged his big man in the waning seconds of a win over Florida State.